我在选项卡式活动上有一个按钮,现在每个活动都被刷过或者选择了另一个选项卡,我想根据片段的索引更改按钮文本。我怎么做?
我刚刚按照本教程创建了android标签: https://www.youtube.com/watch?v=00LLd7qr9sA 它基本上是默认的选项卡式活动,它只是为每个片段创建了一个java和xml文件。
这是我的 main_activity.java
import android.support.design.widget.TabLayout;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity{
private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;
Button buttonChangeMyText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_screen);
buttonChangeMyText= (Button)findViewById(R.id.btnChange);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
anoNa=mViewPager.getCurrentItem();
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main_screen, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/*
@Override
public void onPageSelected(View v) {
TextView tv = (TextView) v.getRootView().findViewById(R.id.textViewSaUna);
tv.setText("Welcome To Android");
}*/
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter{
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
switch (position){
case 0:
Tab1_First tab1 = new Tab1_First();
return tab1;
case 1:
Tab2_Second tab2 = new Tab2_Second();
return tab2;
case 2:
Tab3_Third tab3 = new Tab3_Third();
return tab3;
default:
return null;
}
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "ONE";
case 1:
return "TWO";
case 2:
return "THREE";
}
return null;
}
}//end ng fragment adapter
}
这是片段的java代码。
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
public class Tab1_Una extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.tab1_una, container, false);
return rootView;
}
}
这是main_activity的xml。
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.example.lat.sampletabs.MainScreen">
<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="@dimen/appbar_padding_top"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="@style/AppTheme.PopupOverlay"
>
</android.support.v7.widget.Toolbar>
<android.support.design.widget.TabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.design.widget.AppBarLayout>
<Button
android:id="@+id/btnChange"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="120dp"
android:layout_marginTop="500dp"
android:text="Change the text"/>
<android.support.v4.view.ViewPager
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
答案 0 :(得分:1)
您需要向OnPageChangeListener
添加mViewPager
,如下所示:
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// position = Current tab index being scrolled from
}
@Override
public void onPageSelected(int position) {
// position = New tab index
switch (position) {
case 0:
buttonChangeMyText.setText("Some text");
break;
case 1:
buttonChangeMyText.setText("Some other text");
break;
case 2:
buttonChangeMyText.setText("Some other other text");
break;
// ...
}
}
@Override
public void onPageScrollStateChanged(int state) {
// state = Tells when the user begins dragging, when the pager is
// automatically settling to the current page, or when it is fully stopped/idle.
}
});